The invention is concerned with an apparatus for printing and/or applying self-adhesive labels, which adhere as a strip or separately at equal spacings on a carrier strip which is formed with recesses or marginal indentations which are arranged at spacings which correspond to the spacings of the leading edges of the labels, which is equipped with a feed mechanism which pulls off the carrier strip intermittently for the feeding of a label and which, in conjunction with a device feeling the label carrier strip which is provided with projections engaging in the recesses or marginal indentations of the carrier strip, brings the labels into a printing and/or dispensing position which is to be exactly assumed.
In particular the invention concerns a novel feeding mechanism for the advancing of labels adhering to a carrier strip. Apparatuses for which the novel feeding mechanism may be employed to advantage are, for example, known from U.S. Pat. Nos. 3,265,553; 3,330,207; 3,420,172; 3,440,123; 3,551,251; 3,611,929; 3,619,324; 3,674,609; 3,852,140 and 3,911,817.
What are involved are apparatuses with which adhesive labels can be delivered or applied to articles which are to be labelled. During their travel from a feed roller to the dispensing position, it is also possible to print on the labels. These apparatuses may be constructed as apparatuses which are to be manually operated or they may even be constructed as machines which operate automatically. The labels may adhere with spacings on the carrier strip, but they may also be wholly or partially separated from one another by straight separation cuts or by a perforation. It is also possible to employ label strips which consist of a carrier strip and a paper strip adhering thereto in the form of a band. In this case, after the labels have been printed and after the detachment from the carrier strip, the individual label has to be cut off from the band.
A particular problem which arises with these apparatuses is to control the feeding mechanism acting on the carrier strip such that, with each feeding movement, a label is brought into a dispensing position which is to be accurately maintained and possibly another label is brought into a printing position which is also to be accurately maintained. With the known apparatuses, label strips are used which are provided, for the control of the feeding mechanism, with marginal notches, indentations or cut-outs, which are arranged at intervals corresponding exactly to the distance between the leading edges of the labels. These indentations or the like are explored or scanned mechanically by means of feeler members, which control the pull-off travel of the feed mechanism acting on the carrier strip.
An apparatus for delivering labels is known from U.S. Pat. No. 3,611,929, in which the labels adhere individually and in a row on a carrier strip, which is formed with recesses or marginal indentations which are arranged at intervals which correspond to the distances between the leading edges of the labels, and which is characterized in that a feed roller which can be driven intermittently always by equal angles, is provided on its circumference and in an angular division corresponding to the feeding angle with projections which engage with play in the recesses or marginal indentations of the carrier strip and, in order to produce a sufficiently large frictional force between the carrier strip and the feed roller, the latter is embraced by the carrier strip by an angle which is larger than 120.degree..
This known apparatus has the disadvantage that the tensile force exerted by the feeding or conveying wheel on the label strip is dependent on the frictional forces between the carrier strip and the said roller. These frictional forces may, for example, be greatly reduced by the surface of the feed roller becoming soiled.
This apparatus and all known labelling apparatuses to be manually operated have the additional disadvantage that the empty label-carrying strip is guided out of the apparatus and the end of the strip, after each brief use of the apparatus, has to be torn off, so that it is not in the way.
In order to avoid this last mentioned disadvantage, it is known in connection with electrically driven labelling machines, for example, from U.S. Pat. No. 3,033,417, Van Meer, and U.S. Pat. No. 3,436,294, Marano, to wind the carrier strip for the labels on to a winding drum which can be driven by an electric motor, which is switched on and off by a feeler member which optically or mechanically scans the label strip.
These machines have the disadvantage that they require a source of electrical energy and consequently are unsuitable for apparatuses to be operated manually. A battery and also a conductor for connection to the mains are very inconvenient for labelling apparatuses which are to be manually operated.
Finally, a label-issuing apparatus which is manually operated is known from the German Pat. No. 838,165, with which self-adhesive labels adhering to a carrier strip are individually delivered. The feeding of the labels is effected by means of a winding drum by which the carrier strip freed from labels is wound on step by step. The winding drum is intermittently driven by way of a freewheel clutch, which couples a driving lever in the driving direction to the winding drum. It is not possible with this arrangement to maintain accurately a quite specific feeding distance of the labels, because even with a rocking angle of the driving lever remaining the same, the respective advance of the labels would not be constant, because the feeding distance of the labels is increased as the convolutions of the strip on the winding drum become larger. This feeding mechanism is unsuitable for a labelling apparatus with which the labels have to assume quite an accurate printing position and also an accurate dispensing position.